42nd Ave S Bridge Closure UpdateAs you are likely aware, the 42nd Ave S Bridge was subject to an over height impact from a truck on Wednesday 12/15. The bridge was closed shortly after this incident by the City Police Department and will remain closed until repairs are complete to ensure the safety of all who use this route.
On Thursday 12/16, the King County inspection crew performed an in-depth inspection of the damaged areas. They determined that the truck struck one sway frame of the bridge and inflicted some critical damages to the mentioned sway frame, as well as its associated vertical elements of the through-trusses of the bridge. Fortunately, it appears that no member of the truss bridge has been separated or sheared off, and the damages are limited to the one mentioned sway frame area. This observation was made by TranTech Engineering, LLC, a structural engineering firm that had conducted past structural analysis and is very familiar with this bridge.
On Friday 12/17, the City and TranTech team met a heat straightening contractor, Flame On Inc., at the site and it was determined that this repair is feasible and effective for the observed damages. TranTech recommends that the City obtain the services of this contractor for repair of the described sway frame damages. The King County bridge inspectors are also in agreement with this recommendation.
City staff are moving forward with procuring the contracts necessary to perform the repairs immediately. The Mayor has declared a state of emergency (http://records.tukwilawa.gov/…/2021-12-21%20…) that allows us to move forward quickly. These repairs are weather dependent and may take 4-6 weeks. Additional inspections and structural analysis will determine the future next steps.The bridge closure continues until further notice and City staff will continue to monitor the detour routes.
Thank you for your patience and understanding during this construction period.